Process for the continuous preparation of a di-substituted guanidine



W. P. TER HORST Feb. 14,v 1933.

Filed May '7, 1928 WN IT.

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[NI/ENTOR BY Wmuam D TEQ Hoas 4,70() A TTORNEY Patented Feb. 14, 1933Unirse STATES PATENrosi-ice WILLIAM P. TER HORST, OF NITRO, WESTVIRGINIA, ASSIGNOR T THE RUBBER SERVICE LABORATORIES CO., OF AKRON,OHIO, A CORPORATION 0F OHIO PROCESS FOR THEY CONTINUOUS PREPARATION OF ADI-SUBSTITUTED GUANIDINE Application filed May 7,

The present invention relates to the manufacture of di-substitutedguanidines, particularly the diaryl-guanidines, such asdiphenylguanidine,the ditolyl-guanidines and the like,

by a substantially continuous process, whereby high yields of a pureproduct are realized.

The process will be readily understood from the following descriptionwith reference to the accompanying drawing which rep resents insectional view a preferred arrangement of the apparatus necessary forpracticing the invention.

Referring to the drawing, aniline or other aromatic amine is placed intank 1, from which it is removed through pipe 2, by means of pump 3, andis flowed through pipe 1 into a storage tank 5. From the tank 5 theaniline is flowed through a line controlled by a valve 6 into ameasuring drum 8.

rThe drum 8 is placed upon an ordinary platform scale 7, wherebythe rateof flow of the aniline from the drum is readily ascertained by the lossin weight indicated. The aniline flows from the drum 8 through the pipe9 downward into the tower 10. At the same time, cya-nogen chloride gasfrom any suitable source containing approximately 1.7% moisture isadmitted to the tower 1() through the pipe 14 and passed upward in thetower counter-current to the aniline or other primary aromatic amine,where the two reagents are heated preferably between approximately 90and 115o C. The following reaction takes place if aniline is employed asthe primary aromatic amine:

N H.CGH5

rllhe cyanogen chloride gas admitted by pipe 1lipasses throughflow-meter 16, whereby the rate of flow of cyanogen chloride may bedetermined. The tower 10 is filled with beads l5, as shown, or with anyother substance such as pumice and the like, non-re.- act-ive to thematerials supplied to the tower, and offering an obstructing' orbaffling means to the flow of liquid and gases therethrough.

The tower 10 is surrounded by a heating ele- 1923. Serial No. 275,646.

ment 35, for example a jacket, for the admission of a heating medium,for example steam, by means of valve 27. The steam is allowed to escapefrom the jacket by pipe 29. A line 11, positioned at the bottom ofthetower 10, permits the diphenyl or other diaryl guanidine hydro-chlorideformed by the reaction ofthe amine and cyanogen chloride, to be droppedinto tank 12. This tank is equipped with stirring means 13, Where thesaid diphenyl-guanidine hydrochloride is dissolved in sufficient water,heated by steam from pipe 28, to form approximately a 15% solutionthereof. rlhis solution is withdrawn by pump 17 and forced through pipe18 into chamber 19 and thence into a washing tank 20. Benzol, gasolineor other suitable solvent is supplied to the reaction product run intothe tank 20 as described, in order to remove any uncombined aniline orother amine which may be present. When the washing operation iscompleted, the contents of the tank 2O is allowed to settle, whereuponthe insoluble material, comprising the hydrochloride ofdiphenyl-guanidine, is withdrawn from the tank 20 and flowed through thepipe 24 into tank 23, while the benzol or other solvent employed in thewashing step is removed from the tank 2() by means of pipe 21. The tank23 is previously charged with a solution of alkaline material, forexample a 15% solution of caustic soda, into which thediphenyl-guanidine hydrochloride is run. The acid salt of the arylsubstituted guanidine is thereby neutralized and the free base isobtained. The slurry is agitated by means of stirrer 22 and thesuspension is then removed from tank 23 through the line 26 by means ofpump 25, and is run to a filter press, filtered, washed, dried andground.

Tower 10, hereinbefore mentioned, is provided with exit pipe to allowthe removal of unreacted cyanogen chloride, which is passed by means ofpipe 30 to coil 31, cooled by salt and ice in container 32. From coil31, the condensed cyanogen chloride flows by gravity to storage, forexample a cylinder 33, cooled for example by packing in ice in container34, or may be connected by a pipe to the line 141 leading to the tower10.

Other aryl substituted guanidines may be readily manm'actured in acontinuous manner by employing in place of the aniline mentioned in theexample, other aromatic primary amines, such as ortho-toluidine, the1nand p-to-luidines, the xylidenes and the like. By operating in themanner as described,iit has been found that high yields of an arylsubstituted guanidine may be readily obtained from an aromatic primaryamine. Moreover, the productie of an exceptionally high degree ofpurity.

What is claimed is 1. In the process of manufacturing a di arylsubstituted guanidine by a continuous process, the steps in combinationcomprising continuously flowing vapors of cyanogen chlo- Vridecontaining not more than 1.7% of water a temperature ofapproximately 90 to 115o C.,

removing any unreacted amine from the diaryl guanidine hydrochloride,thus produced by washing with a neutral organic solvent andprecipitating the diaryl guanidine by the addition of an alkali ofconstant strength.

3. In the process-of manufacturing diphenyl-guanidine by a continuousprocess, the steps in combination comprising continuously passing'vaporsof cyanogen chloride containing not more'than 1.7% of watercountercurrent to a stream of aniline in a tower at a temperature ofapproximately from to 115o C., removing any unreacted aniline from thediphenyl gua-nidine hydrochloride thus produced by washing Vwith' aneutral organic solvent, and precipitating the diphenyl guanidine by theaddition of an alkali of constant strength.

4. In the process of manufacturing diphenyl-guanidine by a continuousprocess, the steps in combination comprising continuously passing vaporsof cyanogenchloride containing not more than 1.7% of water upwardcounter-current to a stream of aniline in a tower at a temperature ofapproximately from 90 to 115 C., removing any unreacted aniline from thediphenyl guanidine hydrochloride thus produced by washing with a neutralorganic solvent, and precipitating the diphenyl guanidine by theaddition of an alkali of constant strength.

5. In the process of manufacturing diphenyl-guanidine by a continuousprocess, the

steps in combination comprising continuously passing vapors of cyanogenchloride containing not more than 1.7% of water upward counter-currentto a stream of aniline in a tower at a temperature p of approximatelyfrom 9() to 115o C., removing any unreacted aniline from ythe diphenylguanidine hydrochloride thus produced by washing with benzene, andprecipitating the diphenyl guanivdine by the addition of sodiumhydroxide without the previous addition of a weaker alkali.

6. In the process of manufacturing a diaryl substituted guanidine by acontinuous signature.

WILLIAM P. TER HORST.

